The commonly used thermal or magnetically responsive overload relays with electric motors are not satisfactory when used with such motors driving high inertia loads that require long periods of time to accelerate to normal running speed. Such relays are usually given compromise settings for overload current response which can result in unwanted nuisance tripping. It is therefore desirable to have an overload protection system for such motors that will permit establishment and response to different preset overload current levels during acceleration and normal running, and also provide motor deenergization in the event the motor exceeds a preset time limit in reaching normal running speed.